/* Flot plugin that adds some extra symbols for plotting points.

Copyright (c) 2007-2014 IOLA and Ole Laursen.
Licensed under the MIT license.

The symbols are accessed as strings through the standard symbol options:

    series: {
        points: {
            symbol: "square" // or "diamond", "triangle", "cross"
        }
    }

*/

(function($) {
    function processRawData(plot, series) {
        // we normalize the area of each symbol so it is approximately the
        // same as a circle of the given radius

        var handlers = {
                square: function(ctx, x, y, radius) {
                    // pi * r^2 = (2s)^2  =>  s = r * sqrt(pi)/2
                    var size = radius * Math.sqrt(Math.PI) / 2;
                    ctx.rect(x - size, y - size, size + size, size + size);
                },
                diamond: function(ctx, x, y, radius) {
                    // pi * r^2 = 2s^2  =>  s = r * sqrt(pi/2)
                    var size = radius * Math.sqrt(Math.PI / 2);
                    ctx.moveTo(x - size, y);
                    ctx.lineTo(x, y - size);
                    ctx.lineTo(x + size, y);
                    ctx.lineTo(x, y + size);
                    ctx.lineTo(x - size, y);
                },
                triangle: function(ctx, x, y, radius, shadow) {
                    // pi * r^2 = 1/2 * s^2 * sin (pi / 3)  =>  s = r * sqrt(2 * pi / sin(pi / 3))
                    var size = radius * Math.sqrt(2 * Math.PI / Math.sin(Math.PI / 3)),
                        height = size * Math.sin(Math.PI / 3);
                    ctx.moveTo(x - size / 2, y + height / 2);
                    ctx.lineTo(x + size / 2, y + height / 2);
                    if (!shadow) {
                        ctx.lineTo(x, y - height / 2);
                        ctx.lineTo(x - size / 2, y + height / 2);
                    }
                },
                cross: function(ctx, x, y, radius) {
                    // pi * r^2 = (2s)^2  =>  s = r * sqrt(pi)/2
                    var size = radius * Math.sqrt(Math.PI) / 2;
                    ctx.moveTo(x - size, y - size);
                    ctx.lineTo(x + size, y + size);
                    ctx.moveTo(x - size, y + size);
                    ctx.lineTo(x + size, y - size);
                }
            },
            s = series.points.symbol;

        if (handlers[s]) {
            series.points.symbol = handlers[s];
        }
    }

    function init(plot) {
        plot.hooks.processDatapoints.push(processRawData);
    }

    $.plot.plugins.push({
        init: init,
        name: "symbols",
        version: "1.0"
    });
})(jQuery);
